This invention relates to a foreign substance eliminating apparatus that has a function to capture, during the transfer process, foreign substances mixed into raw material, and a function to remove the foreign substances outside of the transfer path.
There might be various foreign substances already mixed into tobacco leaves, which are the raw materials of cigarette products, before they are supplied to a raw-material factory, for example. On account of this, a method by which all of the tobacco leaves are put through an air blow process to separate the foreign substances and the tobacco leaves using their difference in weight, was adopted as a conventional method to eliminate foreign substances from the tobacco leaves which are the raw material, in the raw-material processing stages of a raw-material factory of tobacco leaves.
However, there are various kinds of foreign substances mixed into the tobacco leaves that are the raw material, varying in their size, their shape, and their weight, and it is very difficult to separate all of the foreign substances from the tobacco leaves uniformly, with the above-mentioned air blow process.
An object of this invention is to provide a foreign substance eliminating apparatus that can effectively eliminate various kinds of foreign substances mixed into raw material.
The foreign substance eliminating apparatus of this invention is provided with: an upstream transfer path that transfers raw material; a downstream transfer path that receives and transfers raw materials falling down from being sent out of the terminus of the upstream transfer path; detecting means for detecting foreign substances from the raw materials being transferred on the upstream transfer path, and outputting a detection signal; deflecting means for deflecting the falling direction of the falling raw material and the foreign substance by ejecting an eliminating airflow towards the falling raw material, when it is determined that there exists a foreign substance within the raw material, based on the above-mentioned detection signal; capturing means for capturing the foreign substance passing through the aforementioned eliminating airflow and falling down, above the downstream transfer path; and eliminating means for removing the foreign substance captured by the capturing means, to the outside of the downstream transfer path.
With the above-mentioned foreign substance eliminating apparatus, the foreign substance and the falling raw material are blown off in the direction of the eliminating airflow, and eliminated instead of falling down onto the downstream transfer path, when a foreign substance is sent out from the terminus of the upstream transfer path. At this point, a relatively large foreign substance passes through the eliminating airflow, and continues to fall down towards the downstream transfer path, and is captured by the capturing means. The captured foreign substance is removed outside of the downstream transfer path by the eliminating means.
The capturing means includes a sieve-surface extending horizontally above the downstream transfer path, and covering the whole width of the downstream transfer path. It is preferred that the eliminating means is composed of a sieve conveyor having a sieve-surface, and that this sieve conveyor can move its sieve-surface in the traversing direction of the downstream transfer path. The foreign substance passing through the eliminating airflow and falling down onto the sieve conveyor is temporarily captured by the sieve-surface of the sieve conveyor. Then, the captured foreign substance is transferred in the traversing direction of the downstream transfer path by the movement of the sieve-surface, and removed outside of this path. On the other hand, the raw material that fell down with the foreign substance onto the sieve-surface, passes through the sieve-surface and drops down onto the downstream transfer path, and continues to be transferred.
The above-mentioned sieve conveyor includes a pair of endless cables, which is arranged on both sides of the sieve-surface and moved in synchronization with each other in the same direction, and also pluralities of rod-form-members that are bridged across the pair of endless cables and arranged in parallel with a prescribed interval, to constitute the sieve-surface. In this case, the sieve mesh is prescribed by the opening between the rod-form-members, and the sieve conveyor carries the rows of rod-form-members in one direction, by the movement of the endless cable.
The sieve conveyor can also have pluralities of sieve-surfaces in vertical layers, and when this is realized, undesired passing through of temporarily captured foreign substances through the sieve-surface is regulated plural times.
In this way, the foreign substance eliminating apparatus of this invention can eliminate various kinds of foreign substances, with high efficiency. And positive elimination of foreign substances, particularly those large foreign substances whose falling down direction is difficult to deflect sufficiently with only the eliminating airflow, contributes a great deal to the improvement in quality of products.
Moreover, when the sieve-surface of the sieve conveyor is constituted by an array of rod-form-members, it can sufficiently withstand the impact of the fall of the foreign substances, and when there are pluralities of sieve-surfaces, the capturing and elimination of the foreign substances can be done more positively.